In order to successfully perforate a well at a desired depth it is necessary to accurately place a shaped charge within an expendable perforating gun tube. Typically an elongated perforating gun barrel is used. Shaped charges are secured into a carrier strip which is in turn secured into the gun barrel. Many different designs of clips have been used. Many different ways of securing the carrier within the gun barrel have also been used. It is the purpose of this invention to solve some of the difficulties encountered in the previous designs.
A retention clip is formed with two facing portions or fingers. These fingers are inserted into an annular groove formed near the perimeter of one end of a shaped charge. The charge and the clip are then inserted into an aperture in a carrier strip. Notches spaced apart from the fingers are cut into the clip so as to fit into and be securely held by the carrier. A "U" shaped portion is formed on the clip to allow a portion of primer cord to pass through and be held by the clip. This improved clip allows the charge to be placed using only one hand. It also forces the charge to stay in place if the carrier is somehow warped.
The carrier is normally placed inside a perforating gun tube. It is desirable to attach the carrier securely within the gun tube. Typically, this has been done by use of a threaded bolt passing through the carrier strip and abuting a portion of the gun tube. This method requires the use of a special angled tool for insertion into the tube to turn the threaded bolt out or in. The current invention solves this problem by providing a cam surface to force a spring-loaded pin outwardly into contact with the tube. The cam surface is part of a set screw which moves along the long axis of the carrier. By turning the set screw the cam surface engages the spring-loaded pin forcing it outwardly. By reversing the set screw the pin is disengaged and the spring-loading forces the pin away from the tube allowing removal of the carrier strip.